Various discussions have hitherto been made as to a dephosphorizing process in sewages, rivers and the like, and pilot experiments have been made in various parts of the country. For example, a method of contact dephosphorization is known, wherein water containing phosphorus is controlled under appropriate conditions to bring into contact with a compound of same species and same system consisting of calcium phosphate, and calcium phosphate (hydroxy apatite) is formed and crystallized on the compound.
In the contact dephosphorization method, the concentration of the phosphorus component in water can be lowered effectively. However, since the phosphorus-containing water requires pH adjustment by a decarboxylating process or addition of lime in order to control such crystallizing reaction, and such control should be made all the time, this method has a drawback to complicate the process. Therefore, the development is desired of a method for effectively removing phosphorus which is economically superior as well as easy and convenient, and of dephosphorizing material which can be used in such a method.